Drug interactions
Imatinib + Tamoxifen
Severity: Moderate
Imatinib and Tamoxifen: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Imatinib inhibits CYP2D6 and CYP3A4 and has been shown to alter tamoxifen metabolite profiles, reducing endoxifen formation. Reduced endoxifen could theoretically lessen tamoxifen benefit.
What this interaction means in plain words
Imatinib and Tamoxifen can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Imatinib belongs to Oncology; Tamoxifen belongs to Endocrine.
Why it happens
Imatinib inhibits CYP2D6 and CYP3A4, reducing tamoxifen bioactivation to endoxifen.
What to do
Monitor treatment response, and consider whether an alternative endocrine agent is suitable if prolonged coadministration is required.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
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Other interactions of Tamoxifen
- Amiodarone + Tamoxifen Major
- Anastrozole + Tamoxifen Major
- Bupropion + Tamoxifen Major
- Carbamazepine + Tamoxifen Major
- Cinacalcet + Tamoxifen Major
- Dacomitinib + Tamoxifen Major
Other interactions of Imatinib
- Imatinib + Lomitapide Contraindicated
- Imatinib + Lonafarnib Contraindicated
- Amobarbital + Imatinib Major
- Apalutamide + Imatinib Major
- Avapritinib + Imatinib Major
- Benzhydrocodone / acetaminophen + Imatinib Major
Frequently asked questions
Can I take Imatinib with Tamoxifen?
MediHelp rates the interaction as moderate. Imatinib and Tamoxifen can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Imatinib inhibits CYP2D6 and CYP3A4 and has been shown to alter tamoxifen metabolite profiles, reducing endoxifen formation. Reduced endoxifen could theoretically lessen tamoxifen benefit.
How serious is the interaction between Imatinib and Tamoxifen?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor treatment response, and consider whether an alternative endocrine agent is suitable if prolonged coadministration is required.
What other medicines interact with Tamoxifen?
MediHelp also lists interactions of Tamoxifen with, for example, Amiodarone, Anastrozole, Bupropion. The full list is on the Tamoxifen page.
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